1666866686877 has 24 divisors (see below), whose sum is σ = 2913514883136. Its totient is φ = 896466116736.

The previous prime is 1666866686867. The next prime is 1666866686899. The reversal of 1666866686877 is 7786866686661.

It is not a de Polignac number, because 1666866686877 - 2²⁰ = 1666865638301 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1666866686796 and 1666866686805.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666866686827) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 778181323 + ... + 778183464.

It is an arithmetic number, because the mean of its divisors is an integer number (121396453464).

Almost surely, 2^{1666866686877} is an apocalyptic number.

1666866686877 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

1666866686877 is a deficient number, since it is larger than the sum of its proper divisors (1246648196259).

1666866686877 is a wasteful number, since it uses less digits than its factorization.

1666866686877 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1556364817 (or 1556364814 counting only the distinct ones).

The product of its digits is 7023034368, while the sum is 81.

The spelling of 1666866686877 in words is "one trillion, six hundred sixty-six billion, eight hundred sixty-six million, six hundred eighty-six thousand, eight hundred seventy-seven".